This site provides two interactive exercises designed to help the user learn about river processes like discharge, flooding and flood frequency. Both exercises require the user to make observations and measurements, do simple calculations, and answer questions. Full description.

This site is a description of the ozone depletion problem with maps, movies and computer simulations of the Antarctic ozone hole. It has a history section, a section on current ozone loss, a detailed section on the chemistry of the stratosphere, and a description of the latest research. Full description.

This is a huge collection of maps showing vegetation around the world. World, regional, and country maps are available. Full description.

The National Weather Service maintains this small series of flooding accounts. The listings include important information on the antecedent conditions in the area of flooding. Most major northeastern floods from the time period of 1927 to the present are discussed. Though the number of examples is small, they represent a diversity of flood conditions and are useful for understanding the critical conditions ... Full description.

This site provides access to water use reports for the country and by county and watershed at five year intervals from 1950 to 2000. There is also a region by region comparison and information about how the data was collected. Full description.